A liquid poured from a container with a narrow neck tends to come out in spurts rather than in a continuous, steady stream. There are numerous applications where waste and spillage results because it is difficult to smoothly pour liquids from a container with a narrow neck. These applications include, but are not limited to, milk jugs, plastic water containers (e.g., one gallon distilled water or mineral water containers); wine bottles and jugs; cooking oil containers; motor oil containers, liquid bleach container, liquid laundry soap container, cleaning fluid containers, and antifreeze containers. In many household applications, the spurting behavior leads to spilled liquids, whether it be milk, wine, or cooking oil. For example, many children spill milk because a tilted milk jug tends to spurt milk during pouring. Also, home cooks often waste cooking oil because it is difficult to smoothly pour a small amount (e.g., one teaspoon) of oil into a measuring utensil or a skillet. The spurting behavior may also lead to contamination of the environment. For example, home auto mechanics often spill motor oil onto the ground because it is difficult to smoothly pour motor oil out from the opening in the neck of a plastic oil container into an oil crankcase. Similarly, home auto mechanics often spill anti-freeze because anti-freeze spurts out from the container during pouring. Although funnels can be used to mitigate this problem, funnels may not be available, are inconvenient to use, and also dribble fluid after they are used.
The spurting behavior of a liquid being poured from a container is a consequence of well-known principles of fluid mechanics. The forces acting on a column of liquid in a container include a gravitational force and the force of the atmosphere. When a container with a narrow neck is tilted at a steep angle, liquid initially smoothly pours out of the opening in the neck of the container because of the force of gravity acting upon the fluid column. However, as liquid is discharged from the container, a vacuum tends to form in the container, particularly if the container has substantially rigid walls. Air will intermittently re-enter the container to replace the volume of the discharged fluid. Consequently, the pressure of the discharged fluid varies over time as air is intermittently admitted into the container.
The spurting behavior affects the velocity of the fluid exiting the opening or orifice of a tilted container. This changes the transverse distance the fluid stream extends as it falls, which makes it difficult to accurately pour liquid from a tilted container. For example, the fluid stream from the opening in the neck of a tilted motor oil container tends to move transversely back and forth, making it difficult to safely pour oil into the oil filler passage of a car without using a wide funnel.
One attempted solution to prior art fluid pouring problems is a seal that prevents the flow of a fluid until the container is in a desired up-ended pouring position. For example, U.S. Pat. No. 4,696,328 discloses a motor oil container that has a frangible seal. As is taught in that patent, after the neck of the oil container is inserted into the oil filler passage of a car a frangible seal is ruptured by compressing the container such that the pressure breaks the frangible seal. This prevents the type of spillage that would occur if an open neck container was poured from a distance into the oil filler passage. However, once the frangible seal is ruptured, the fluid still comes out in spurts until the container is empty. Thus, the container of U.S. Pat. No. 4,696,328 has limited applications. For example, the teachings of U.S. Pat. No. 4,696,328 are inapplicable to consumer products, such as milk containers, where it is desirable to smoothly pour a small quantity of liquid many times from the same container.
Still another attempted solution to prior art fluid pouring problems is a container having a hinged sealing cap that permits the user to maintain the cap in a closed position until the container is inverted to a pouring position. For example, U.S. Pat. No. 5,105,986 discloses a flow control device comprised of a closure member coupled by a hinge to the neck region of the flow control device having the fluid opening. The closure member is biased by the hinge to maintain the closure member in a substantially non-obstructing open position. Consequently, during normal use, the closure member does not affect the flow of liquid from the opening in the neck of the container. However, the user may manually press the closure member into a sealed position about the opening to prevent the flow of liquid from the container through the opening until the container is properly positioned. The hinged flap of U.S. Pat. No. 5,105,986 is useful to prevent spillage of oil, cleaning fluid, and other liquids. However, there are some significant drawbacks to the biased closure member of U.S. Pat. No. 5,105,986. One drawback is that the closure member may be difficult to use on large or heavy containers. For example, a one gallon anti-freeze container is heavy enough that adults typically need to grasp the container with all five fingers. That is, it may be difficult for many home mechanics to grasp the container with four fingers while using their thumb to close the closure member. Another drawback is that a closure member controlled by finger pressure may not be suitable for liquid beverages, such as milk, because of potential contamination problems. As taught in U.S. Pat. No. 5,105,986, the closure member is in close proximity to the orifice from which liquid flows. This makes it likely that a user, particularly a child with poor eye-hand coordination, would touch the lip of the orifice. Still another shortcoming of the closure flap of U.S. Pat. No. 5,105,986 is that it does not address the problem of spurting. When the closure member is in its normal, non-obstructing position it does not affect the flow of fluid from the container. Consequently, the closure flap of U.S. Pat. No. 5,105,986 does not provide a physical mechanism to substantially improve the flow behavior at low flow rates. For example, the closure flap of U.S. Pat. No. 5,105,986 would not assist a cook to smoothly pour a small quantity (e.g., one-half teaspoon) of liquid seasoning into a measuring spoon.
No previously known pour flow control device provides a simple physical mechanism to mitigate the spurting problem associated with pouring a liquid from the orifice of a container. No previously known pour flow control device adequately addresses the problem of increasing the ability of a user to smoothly control the rate of fluid flow from a container.
What is desired is pour flow control device which facilitates a steady flow of liquid from the orifice of a container.